1. Field of the Invention
The present invention relates to a polysilane capable of crosslinking to form a two dimensional or three dimensional polymer. The invention also relates to a composition which contains a polysilane incapable of crosslinking by itself, but is capable of forming such a polymer.
2. Description of the Related Art
Vigorous researches are being made on the application of a polysilane in various fields such as a precursor of a ceramic material, an electrically conductive material, a photoconductive material, a semiconductor material and a non-linear optical material. Of course, the polysilane is a highly interesting material in the industry.
The polysilane which has attracted attentions in the past has in general hydrophobic side chains such as an alkyl group and a phenyl group bonded to the Si--Si backbone, that is to say, the Si--Si main chain. On the other hand, polysilanes having a polar group in the side chain are also disclosed in, for example, "Macromolecule, 22 (1989), page 293", "Macromolecule, 21 (1988), page 304", and Published Unexamined Japanese Patent Application No. 1-311102. Polysilanes having a polar group in the side chain exhibit an excellent affinity with an organic solvent and, thus, can be dissolved in the organic solvent to form a solution. It follows that the polysilanes having a polar group in the side chain can be processed easily to various materials exemplied above. For example, a thin film of such a polysilane can be formed by means of a rotary coating method.
However, the polysilane which attracted attentions in the past has a substantially one dimensional molecular structure, i.e., a linear structure. It follows that, when formed into, for example, a thin film, the bond strength between the polysilane thin film and the substrate is low. Also, the conventional polysilane has in general a low glass transition point Tg. It follows that the polysilane is insufficient in its heat resistance. Besides, the conventional polysilane is poor in its wear resistance. Therefore, it is necessary to solve various problems before the conventional polysllane is put to a practical use.